The present invention generally relates to a carrying barge for carrying loads such as soil and sand, buiding stones, etc. to be expelled from a hold of the barge at a predetermined place in the sea, and more particularly, to an improvement in the watertightness of a two-split type carrying barge in which right and left hulls are arranged to be rotated to open the bottom of a hold at the center line when the load is to be expelled.
Conventionally, cargo, soil and sand or the like have been loaded and carried by a steel lighter or a steel barge of the type shown in FIG. 17, the bottom of a hold A of which is not opened, or a carrying boat as shown in FIG. 18(A) having a door B formed in the lower right and left sides of the hold A, or a two-split type carrying boat as shown in FIG. 19 which has a main hull divided into right and left portions which are arranged to be rotated to open the hold.
Although the carrying boat shown in FIG. 17 is free from the undesired possibility of the load getting wet, it has such a drawback in that the load, if it comprises particle or powdery goods, is difficult to be completely expelled. The carrying boat of FIG. 18 is convenient when particle or powdery goods are expelled. However, the watertightness cannot be secured in the carrying boat of FIG. 18 and, therefore, the kind of cargo to be loaded in the carrying boat of FIG. 18 is limited. Furthermore, if the goods get wet because of the poor watertightness of the carrying boat of FIG. 18, the total weight of the goods loaded is increased, resulting in an uneconomical requirement for a large hull of the carrying boat.
On the other hand, the two-split type carrying boat shown in FIG. 19 is comprised of left and right rotatable hull parts 1 and 2, fixed front and rear hull parts 3 and 4 which constitute a machine room, etc., and a hold 5 defined by the left and right hull parts 1 and 2. The left and right hull parts 1 and 2 are arranged to be rotated, as shown in FIG. 19, at the fulcrum of hinges 6 respectively provided at the bow side and the stern side of the boat, so that the bottom of the boat is opened to open the hold 5. The above-described two-split type is advantageous in that the loaded cargo can be conveniently expelled, and moreover, a large capacity of the hold can be obtained in comparison with the size of the hull. However, in the carrying boat having the above-described structure, since the watertightness at the opening portion between the right and left hull parts at the center line L of the bottom of the hold 5 is secured only by a rubber packing 7, and moreover, the two hinges 6 hold the hull parts over the long distance from the bow to the stern of the boat, the left and right hull parts 1 and 2 are apt to be affected by different curves or vibrations from each other during navigation or upon the application of shocks thereto. In such a case, the water tightness at the opening portion of the hold 5 can not be secured only by the above rubber packing 7, resulting in the passage of water into these hold. In the circumstances, therefore, the length of the hold has conveniently been more or less than 30 m, and the loading capacity is restricted to 2-3000 tons. Thus, the above-described two-split type has been employed in a relatively small carrying boat, but can not be utilized in a large carrying boat.